The invention relates to electrostatic precipitators or collectors, including for diesel engine electrostatic crankcase ventilation systems for blowby gas for removing suspended particulate matter including oil droplets from the blowby gas.
Electrostatic precipitators, including for diesel engine electrostatic crankcase ventilation systems, are known in the prior art. In its simplest form, a high voltage corona discharge electrode is placed in the center of a grounded tube or canister forming an annular ground plane providing a collector electrode around the discharge electrode. A high DC voltage, such as several thousand volts, e.g. 15 kV, on the center discharge electrode causes a corona discharge to develop near the electrode due to high electric field intensity. This electric field ionizes the gas in such corona discharge ionization zone, which in turn creates ions which in turn electrically charge suspended particles in the gas. The charged particles are in turn precipitated electrostatically onto the interior surface of the collecting tube or canister, i.e. attracted to such ground plane. Electrostatic collectors have been used in diesel engine crankcase ventilation systems for removing suspended particulate matter including oil droplets from the blowby gas, for example so that the blowby gas can be returned to the atmosphere, or to the fresh air intake side of the diesel engine for further combustion, thus providing a blowby gas recirculation system. The oil mist collects on the ground electrode provided by the canister, which collected oil mist is drained from the unit.
The present invention arose during continuing development efforts directed toward improved performance of an electrostatic precipitator, including reducing contamination of the ground electrode, including the noted oil mist collected on the annular ground plane canister in a diesel engine electrostatic crankcase ventilation system application.